From: Ruediger Pluem <rpluem@apache.org>
Date: Tue, 8 Feb 2011 10:16:05 +0000 (+0000)
Subject: Merge r1001884 from trunk:
X-Git-Tag: 2.2.18~154
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a6f9c3f5b1b309022a7cc65b19998f4a2e4056a9;p=thirdparty%2Fapache%2Fhttpd.git

Merge r1001884 from trunk:

mod_cache: Make sure that we never allow a 304 Not Modified response
that we asked for to leak to the client should the 304 response be
uncacheable. PR45341

Submitted by: minfrin
Reviewed by: minfrin, jim, covener


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1068313 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/CHANGES b/CHANGES
index 1703fad57f1..81e4d597a0a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,10 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.2.18
 
+  *) mod_cache: Make sure that we never allow a 304 Not Modified response
+     that we asked for to leak to the client should the 304 response be
+     uncacheable. PR45341 [Graham Leggett]
+
   *) mod_dav: Send 501 error if unknown Content-* header is received for a PUT
      request (RFC 2616 9.6). PR 42978. [Stefan Fritsch]
 
diff --git a/STATUS b/STATUS
index b03427fa299..5bf71144e29 100644
--- a/STATUS
+++ b/STATUS
@@ -90,13 +90,6 @@ RELEASE SHOWSTOPPERS:
 PATCHES ACCEPTED TO BACKPORT FROM TRUNK:
   [ start all new proposals below, under PATCHES PROPOSED. ]
 
-   * mod_cache: Make sure that we never allow a 304 Not Modified response
-     that we asked for to leak to the client should the 304 response be
-     uncacheable.
-     PR45341
-     Trunk patch: http://svn.apache.org/viewvc?view=revision&revision=1001884
-     2.2.x patch: http://people.apache.org/~minfrin/httpd-mod_cache-304-fix-2.patch
-     +1: minfrin, jim, covener
 
 PATCHES PROPOSED TO BACKPORT FROM TRUNK:
   [ New proposals should be added at the end of the list ]
diff --git a/modules/cache/mod_cache.c b/modules/cache/mod_cache.c
index 162773f99e5..8aeb3f73ca7 100644
--- a/modules/cache/mod_cache.c
+++ b/modules/cache/mod_cache.c
@@ -585,6 +585,52 @@ static int cache_save_filter(ap_filter_t *f, apr_bucket_brigade *in)
         reason = "r->no_cache present";
     }
 
+    /* Hold the phone. Some servers might allow us to cache a 2xx, but
+     * then make their 304 responses non cacheable. This leaves us in a
+     * sticky position. If the 304 is in answer to our own conditional
+     * request, we cannot send this 304 back to the client because the
+     * client isn't expecting it. Instead, our only option is to respect
+     * the answer to the question we asked (has it changed, answer was
+     * no) and return the cached item to the client, and then respect
+     * the uncacheable nature of this 304 by allowing the remove_url
+     * filter to kick in and remove the cached entity.
+     */
+    if (reason && r->status == HTTP_NOT_MODIFIED &&
+             cache->stale_handle) {
+        apr_bucket_brigade *bb;
+        apr_bucket *bkt;
+        int status;
+
+        cache->handle = cache->stale_handle;
+        info = &cache->handle->cache_obj->info;
+
+        /* Load in the saved status and clear the status line. */
+        r->status = info->status;
+        r->status_line = NULL;
+
+        bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
+
+        r->headers_in = cache->stale_headers;
+        status = ap_meets_conditions(r);
+        if (status != OK) {
+            r->status = status;
+
+            bkt = apr_bucket_flush_create(bb->bucket_alloc);
+            APR_BRIGADE_INSERT_TAIL(bb, bkt);
+        }
+        else {
+            cache->provider->recall_body(cache->handle, r->pool, bb);
+        }
+
+        cache->block_response = 1;
+
+        /* let someone else attempt to cache */
+        ap_cache_remove_lock(conf, r, cache->handle ?
+                (char *)cache->handle->cache_obj->key : NULL, NULL);
+
+        return ap_pass_brigade(f->next, bb);
+    }
+
     if (reason) {
         ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
                      "cache: %s not cached. Reason: %s", r->unparsed_uri,